Laterally insertable intervertebral spinal implant

ABSTRACT

An intervertebral implant for implantation in an intervertebral space between vertebrae. The implant includes a body having a front end, a rear end and a pair of spaced apart first and second side walls extending between the front and rear ends. The front and rear ends extend in a transverse direction and a central axis of the body extends from the rear end to the front end. The rear end defines a first fastener hole having a first central axis and a second fastener hole having a second central axis. The first and second central axes extend parallel to one another at an acute angle relative to the body central axis in the transverse direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 16/205,892, filed on Nov. 30, 2018, which is acontinuation application of U.S. patent application Ser. No. 15/954,655filed on Apr. 17, 2018 which is a divisional of U.S. patent applicationSer. No. 14/509,634, filed Oct. 8, 2014, which is a continuation-in-partof U.S. patent application Ser. No. 14/278,898 filed on May 15, 2014,the entire disclosures of which are incorporated herein by reference intheir entireties for all purposes.

FIELD

The present disclosure generally relates to fixation devices and systemsfor positioning and immobilizing at least two adjacent vertebrae andmethods related to the same. In particular, the present disclosurerelates to interbody fusion devices with angled fixation holesconfigured to facilitate lateral arterial implantation.

BACKGROUND

The spine is the axis of the skeleton on which all of the body parts“hang”. In humans, the normal spine has seven cervical, twelve thoracicand five lumbar segments. The lumbar spine situs upon the sacrum, whichthen attaches to the pelvis, and in turn is supported by the hip and legbones. The bony vertebral bodies of the spine are separated byintervertebral discs, which act as joints but allow known degrees offlexion, extension, lateral bending, and axial rotation.

The typical vertebra has a thick anterior bone mass called the vertebralbody, with a neural (vertebral) arch that arises from the posteriorsurface of the vertebral body. The central of adjacent vertebrae aresupported by intervertebral discs. The spinal disc and/or vertebralbodies may be displaced or damaged due to trauma, disease, degenerativedefects, or wear over an extended period of time. One result of thisdisplacement or damage to a spinal disc or vertebral body may be chronicback pain. In many cases, to alleviate back pain from degenerated ofherniated discs, the disc is removed along with all or part of at leastone neighboring vertebrae and is replaced by an implant that promotesfusion of the remaining bony anatomy.

Although most spinal surgeries are performed using a posterior (back)approach, in some cases a surgeon may choose an anterior (ALIF) approachfor various reasons, for example, to allow more direct access to theintervertebral disk; to have the ability to add more lordosis (swayback)to the d spine; and to provide access to the spine without moving thenerves. Treatment of the disc at the L5/S1 level is particularlysuitable for the ALIF approach due to the efficient vascular accessbelow with bifurcation of the aorta and inferior vena cava. However, theALIF approach typically requires organs and blood vessels be moved tothe side. As such, in many cases, a vascular surgeon assists theorthopaedic surgeon with opening and exposing the disk space.

Additionally, the ALIF approach is typically performed with the patientin a supine position. As such, other procedures, for example, attachinga plate or rod to posterior spine, will generally require changing theposition of the patient to provide posterior axis. The result is oftenincreased surgical time and reduced surgical workflow.

SUMMARY

To meet this and other needs, an intervertebral implant has an overallfootprint that matches that of a standard integrated-fixation ALIF,however, the means of attachment to the device and the angle at whichthe fixation is delivered, sit at an angle relative to the disc space.

According to at least one embodiment of the disclosure, an insertiontool and intervertebral implant kit is disclosed. The implant includes abody having a front end, a rear end and a pair of spaced apart first andsecond side walls extending between the front and rear ends. The frontand rear ends extend in a transverse direction and a central axis of thebody extends from the rear end to the front end. The rear end defines afirst fastener hole having a first central axis and a second fastenerhole having a second central axis. The first and second central axesextend parallel to one another at an acute angle relative to the bodycentral axis in the transverse direction. The insertion tool includes atool body extending from a proximal end to distal end. The distal enddefines a face and the tool body defines at least two fastener passageswith respective third and fourth central axes. The insertion tool isconfigured to support the implant such that the implant rear end extendsalong the face and the third and fourth central axes align with and areparallel to the first and second central axes, respectively, in thetransverse direction.

According to at least one embodiment of the disclosure, a retractionassembly is disclosed. The retraction assembly includes a mounting platewith at least one mount extending therefrom. The mounting plate has achamber extending therein with an adjustment screw extending into thechamber. A lateral adjustment arm has a first end with a shaft which ispositioned in the chamber and engages the adjustment screw such thatrotation thereof causes the lateral adjustment arm to move laterallyrelative to the mounting plate. The second end of the lateral adjustmentarm defines a pivot mount. A pivot member is pivotally connected to thelateral adjustment arm at the pivot mount with a second adjustment screwextending from the lateral adjustment arm and engaging the pivot membersuch that rotation thereof causes pivoting of the pivot member relativeto the lateral adjustment arm. A retraction blade connected to the pivotmember.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a bottom perspective view of an intervertebral implantaccording to an embodiment of the disclosure.

FIG. 2 is anterior elevation view of the intervertebral implant of FIG.1.

FIG. 3 is bottom plan view of the intervertebral implant of FIG. 1.

FIG. 4 is a perspective view similar to FIG. 1 illustrating fastenerspositioned within the implant.

FIG. 5 is a cross-sectional view of the anterior portion of the implantof FIG. 1 with a locking screw positioned therein.

FIG. 6 is a top plan view of the intervertebral implant of FIG. 1positioned relative to a vertebra.

FIG. 7 is a perspective view illustrating the intervertebral implant ofFIG. 1 connected to an insertion tool in accordance with an embodimentof the disclosure.

FIGS. 8-10 are perspective, side and elevation views, respectively, of aretraction blade in accordance with an embodiment of the disclosure.

FIGS. 11-13 are perspective, side and elevation views, respectively, ofa retraction blade in accordance with another embodiment of thedisclosure.

FIG. 14 is a perspective view of the retraction blade of FIGS. 8-10positioned in a mounting system in accordance with an embodiment of thedisclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure are generally directed to intervertebralimplants, systems, and method of use thereof.

Referring to FIGS. 1-7, an embodiment of a lateral anterior lumbarinterbody fusion implant 110 in accordance with an embodiment of thedisclosure will be described. As illustrated, the implant 110 has a body111 with a generally D-shaped configuration. The body 111 is defined bya posterior end 112, an anterior end 114 and side walls 116 and 118extending therebetween. A hollow interior chamber 113 is defined withinan inner perimeter of the body 111. The hollow interior chamber 113 isconfigured to receive bone growth promoting materials. The implant 110has an upper surface 120 and a substantially parallel lower surface 122.It is noted that in FIGS. 1-4, the implant 110 is illustrated in aninverted position such that the lower or superior surface 122 is facingupward. The upper and lower surfaces 120, 122 define a plurality ofserrations 117 along the side walls 116, 118 and a plurality ofserrations 119 along the posterior end 112.

While the implant 110 is illustrated and described with a body 111having a specific configuration, the disclosure is not limited to such.The body 111 may have various other configurations suitable for the discspace into which the implant 110 is intended. For example, the posteriorend 112 may be formed with a taper or the implant 110 may have a wedgeshape such that the entire body 111 tapers from the anterior end 114 tothe posterior end 112. Similarly, the side walls 116, 118 may be angledtoward one another rather than extending substantially parallel to oneanother. As yet another example, the body 111 may have an adjustableconfiguration. In each case, the implant body 111 will have a centralaxis CA extending from the anterior end 114 to the superior end 112. Thecentral axis CA is located at the junction between the mid transverseplane P1 and the mid sagittal plane P2 and extends in each of the planesP1, P2 (see FIG. 2).

The anterior end 114 of the implant 110 includes a plurality of fastenerholes 124, 126 through which anchors 140 or screws 150 (see FIGS. 4 and6) extend to anchor the implant onto the vertebral body. Each of thefastener holes 124, 126 has a central axis C1, C2, C3. As is known inthe art, the axes C1, C2, C3 may be angled superiorly or inferiorlyrelative to the transverse plane P1 such that the fasteners will bedirected toward the superior or inferior vertebral body. In theillustrated embodiment, the axes C1, C2 of fastener holes 124 eachextend inferiorly relative to the transverse plane P1 and the axis C3 ofthe fastener hole 126 extends superiorly relative to the transverseplane P1. Such configuration is not required and the implant may haveother configurations with more or fewer holes and with different numbersof holes extending superiorly or inferiorly. Additionally, whenutilizing anchors 140 such angling may not be as necessary or necessaryat all since the curved configuration of the anchor blade body 142 iscurved and will naturally extend superiorly or inferiorly.

Secondary holes 125 are provided to receive respective blocking setscrews 160 (see FIG. 5). The secondary holes 125 each extend along acentral axis C6, C7. Each of the secondary hole axes C6, C7 is generallyparallel to the transverse plane P1. A blind hole 127 with a slot 129and a threaded hole 128 are provided for receiving an instrument 170that is used for inserting the implant 110, as will be describedhereinafter. The central axis C4 of the blind hole 127 and the centralaxis C5 of the threaded hole 128 also are generally parallel to thetransverse plane P1.

In addition to the angular orientation in the superior/inferiordirection, each of the axes C1-C7 is also angled relative to thesagittal plane P2 (and thereby the central axis CA) in the transversedirection to facilitate lateral insertion of the implant 110. Referringto FIG. 3, the axes C1 and C2 are parallel to one another and each areangled relative the sagittal plane P2 at an acute angle α. While notshown in FIG. 3, the axis C3 of fastener hole 126 will also be angledrelative the sagittal plane P2 at the acute angle α and will be parallelto the axes C1 and C2. As seen in FIG. 6, upon fixation of the implant110 relative to the vertebral body 12 of the spine 10, the shaft 142,152 of each of the fasteners 140, 150 will parallel to each other in thetransverse direction, each extending at the angle aα relative to thecentral axis CA of the implant 110.

The angle α is chosen to approximate the angle of the lateral insertionpath A of the implant relative to the sagittal plane SP of the vertebralbody 12 of the spine 10 as shown in FIG. 6. As shown in FIG. 7, suchallows the insertion tool 170 to hold the implant for insertion alongthe path A and also allows the fasteners 140, 150 to be delivered alongthe same path along which the insertion tool will extend. Upon properpositioning, the central axis CA of the implant 110 will extendapproximately along the sagittal plane SP of the vertebral body 12 andthe fasteners 140, 150 may be easily directed into engagement with thesuperior and inferior vertebral bodies.

Referring to FIG. 4, to facilitate easy mounting of the insertion tool170 relative to implant 110, the axis C4 of the blind hole 127 and theaxis C5 of the threaded hole 128 also extend parallel to the fastenerhole axes C1-C3. As such, the insertion tool 170 may be delivered to theimplant 110 along the path A and then a threaded connector (not shown)can be advanced parallel to the axis of the tool 170.

Referring to FIG. 5, to facilitate easy engagement of the blocking setscrews 160, the axes C6, C7 of the secondary holes 125 also preferablyextend parallel to the fastener hole axes C1-C3. With the shaft 162 ofeach blocking set screw 160 extending into a respective secondary hole125, the head 164 thereof will be co-axial with the secondary hole 125.As such, a driver (not shown) may be moved along at the same angledefined by the insertion tool 170 to engage the head 164 and move theset screw 160 from a non-blocking position, wherein the recess(es) 166on the head 164 are aligned with a respective fastener hole 124, 126, toa blocking position wherein the head 164 overlies the fastener holes124, 126.

Having generally described the implant 110, the insertion tool 170 andimplant procedure will be described in more detail with reference toFIG. 7. The insertion tool 170 includes a main body 172 extending from aproximal end 171 to a distal end 173 along a tool central axis C8. Thedistal end 173 defines a face 175 configured to engage the anterior end114 of the implant 110. The face 175 is angled relative to the toolcentral axis C8 such that upon mounting of the implant 110 on the tool170, the tool central axis C8 will be parallel with the central axesC1-C7 of the implant in the transverse direction. The tool body 172 maydefine one or more openings 179 configured to mount other tools thereto,for example, an articulating table arm or a pushing handle (not shown).

To connect the insertion tool 170 to the implant 110, a pin (not shown)extends from the tool face 175 at the location labeled 177 which alignswith the blind hole 127 of the implant. The pin extends along an axis C9which is parallel to the tool central axis C8 such that the pin willextend into the blind hole 127 and the face 175 will extend along theanterior end 114 of the implant 110. A threaded connector (not shown)extends through a passage in the insertion tool 170 such that thethreaded connector extends from the face 175 at the location labeled 178which aligns with the threaded hole 128. The tool 170 may include ahandle portion 176 through which the connector passage extends. Thethreaded connector passage extends along an axis C10 that is parallelwith the tool central axis C8 such that the threaded connector can beadvanced into and threadably engage the threaded hole 128, therebymounting the implant 110 to the face 175 of the insertion tool 170.

The tool body 172 defines fastener passages 182, 184 (only two shown inFIG. 7) configured to align with each of the fastener holes 124, 126.The axes C11, C12, C13 of the fastener passages 182, 184 extend parallelto the tool central axis C8. As such, the fasteners 140, 150 may beeasily passed through the insertion tool 170 into the respectivefastener hole 124, 126. In the event a curved anchor blade 142 isutilized, the passages 182, 184 may have corresponding curves (in thesuperior/inferior direction). An alignment hole 183, 185, 187 extendsinto each of the fastener passages 182, 184.

To access the blocking set screws 160, an opening 186 extends into thebody 172 to set screw passages 188 on either side of the tube 180defining the fastener passage 182. Each set screw passage 188 alignswith a respective secondary hole 125. The axes C14, C15 of the set screwpassages 188 extend parallel to the tool central axis C8. As such, adrive tool (not shown) may be passed through each set screw passage 188to engage and rotate a respective set screw 160. Alignment holes 189,190 extend into each of the set screw passages 188.

While the illustrated embodiments have a fixed angle α for the holes andtool passages, it is possible to make the angle adjustable such that theimplant 110 may be adjustable for different anatomies. For example, eachof the implant holes could include a ball and socket configuration whichis lockable at a desired angle. The face of the insertion tool could bepivotably adjustable to match the angle set for the implant holes. Othermeans for adjusting the angle of the holes and the tool passages mayalso be utilized.

The implant 110 and insertion tool 170 provide greater ease of useoff-axis to disc spaces, for example, the L5-S1 disc space. TraditionalALIF implants require a straight-on approach, which is made moredifficult when the patient is positioned on their side. The angledapproach to the disc space with the angled tool, paired with a matchingangle by which the fixation is delivered and blocked in placefacilitates operating on the L5-S1 disc space, or other desired discspaces, via a lateral position, or “lateral ALIF”.

Such lateral ALIF requires retraction of different anatomy to access thedisc space with a patient on their side. Referring to FIGS. 8-14, aretraction assembly 220 which offers increased ability to adjust bladeposition as well as specific options for retracting the anatomy as itpertains to accessing the disc space with a patient on their side willbe described.

Referring to FIGS. 8-10, an illustrative blade 200 for use with theretraction assembly 220 illustrated in FIG. 14 will be described. Theblade 200 includes a body 202 extending from a proximal end 201 to adistal end 203. The distal end 203 of the body 202 includes a portion204 having a narrower width than the portion 208 at the proximal end201. The body 202 may have a lateral curvature as illustrated.Additionally, a curved tip 206 is defined at the distal end 203 of thebody 202. The curved tip 206 may also narrow as it moves distally. Thenarrow portion 204 and the curved tip 206 allow for retraction ofvasculature, for example, at the crotch of the bifurcation. The widerportion 208 at the proximal end 201 provides better retraction of softtissue. The bi-functionality of the blade 200 serves well for aminimally invasive anterior approach where the vessels need to bemobilized. A flange portion 212 extends from the proximal end 201 andsupports a connecting member 214 configured to engage and mount to apivoting member 250 of the retraction assembly 220 as will be describedhereinafter.

Referring to FIGS. 11-13, another illustrative blade 200′ for use withthe retraction assembly 220 illustrated in FIG. 14 will be described.The blade 200′ includes a body 202′ extending from a proximal end 201′to a distal end 203′. The body 202′ tapers in thickness from a thinnerportion 205 at the proximal end 201′ to a thicker portion at the distalend 203′. This configuration serves to stiffen the blade 200′. Again,the body 202′ may have a lateral curvature as illustrated. Additionally,a scalloped tip 209 is defined at the distal end 203′ of the body 202′.The scalloped tip 209 may be used to sit under bony anatomy and act as alever for retracting soft tissue. Again, a flange portion 212 extendsfrom the proximal end 201′ and supports a connecting member 214configured to engage and mount to a pivoting member 250 of theretraction assembly 220.

Referring to FIG. 14, a retraction assembly 220 in accordance with anembodiment of the disclosure will be described. The retraction assembly220 includes a mounting plate 222 with one or more mounts 224 extendingtherefrom. The mounts 224 are configured for mounting directly to anarticulating table arm 230 or other structure, for example, mounting toextensions which mount to a more traditional ring-based design. In theillustrated embodiment, the table arm 230 includes an arm 232 whichterminates in a screw platform 234 supporting a connecting screw 236.The connecting screw 236 is positioned within the mount 224 andtightened such that the mount 234 is secured between the head of thescrew 236 and the screw platform 234 to secure the mounting plate 222.

A cavity 225 extends into the mounting plate 222 and is configured toreceive a shaft 242 of a lateral adjustment arm 240. The shaft 242defines a slot 244 into which an adjustment screw 226 of the mountingplate 222 extends. The screw 226 engages within the slot 244 and therebydefines the range of later movement of the lateral adjustment arm 240.The screw 226 and slot 244 may have various adjustment configurations,for example, a friction lock, gear assembly, or a rack and pinionarrangement.

The opposite end of the lateral adjustment arm 240 defines a fork 248with a pair of openings 249 on each side to support a pivot member 250.The pivot member 250 includes a body 252 with an opening configured toreceive the blade connecting member 214 to mount the blade 200 on theassembly 220. A pivot pin 256 extends through the fork 248 and end ofthe pivot member body 250 such that the pivot member 250 is pivotallysupported relative to the fork 248. A pair of opposed extensions 254extend into the openings 249 and define the range of pivot. Anadjustment screw 246 on the lateral adjustment arm 240 engages anopposite end of the pivot member 250 such that rotation thereof causesthe pivot member 250, and thereby the blade 200, to pivot. Pivoting ofthe blade 200 allows the blade 200 to change angulation to compensatefor various anatomy and tissue.

Although the invention has been described in detail and with referenceto specific embodiments, it will be apparent to one skilled in the artthat various changes and modifications can be made without departingfrom the spirit and scope of the invention. Thus, it is intended thatthe invention covers the modifications and variations of this inventionprovided they come within the scope of the appended claims and theirequivalents. It is expressly intended, for example, that all rangesbroadly recited in this document include within their scope all narrowerranges which fall within the broader ranges. It is also intended thatthe components of the various devices disclosed above may be combined ormodified in any suitable configuration.

What is claimed is:
 1. An insertion tool and intervertebral implant kit,the kit comprising: an implant comprising: an implant body having afront end, a rear end and a pair of spaced apart first and second sidewalls extending between the front and rear ends with the front and rearends extending in a transverse direction and a central axis of theimplant body extending from the rear end to the front end, wherein therear end defines a first fastener hole having a first central axis and asecond fastener hole having a second central axis, the first and secondcentral axes extending parallel to one another at an acute anglerelative to the implant body central axis in the transverse direction;and an insertion tool comprising: a tool body extending from a proximalend to distal end, the distal end defining a face and the tool bodydefining at least two fastener passages with respective third and fourthcentral axes, wherein the insertion tool is configured to support theimplant such that the implant rear end extends along the face and thethird and fourth central axes align with and are parallel to the firstand second central axes, respectively, in the transverse direction. 2.The kit of claim 1, wherein the implant rear end defines a thirdfastener hole having a fifth central axis which is parallel to the firstand second axes in the transverse direction and the insertion tool bodydefines a third fastener passage having a sixth central axis whichaligns with and is parallel to the fifth central axis in the transversedirection when the implant is supported on the insertion tool.
 3. Thekit of claim 1, wherein the first central axis extends in a firstdirection relative to a superior/inferior direction and the secondcentral axis extends in a second opposite direction relative to thesuperior/inferior direction.
 4. The kit of claim 1, wherein at least oneblocking set screw hole is defined by the implant rear end adjacent atleast one of the fastener holes, the blocking set screw hole having aseventh central axis which is parallel to the first and second axes inthe transverse direction and the insertion tool body defines a driverpassage having an eigth central axis which aligns with and is parallelto the seventh central axis in the transverse direction when the implantis supported on the insertion tool.
 5. The kit claim 4, furthercomprising a blocking set screw positioned within the blocking set screwhole and moveable between a non-blocking position and a blockingposition by a driver positioned within the driver passage.
 6. The kit ofclaim 1, wherein at least one insertion tool receiving hole is definedby the rear end and has a ninth central axis which is parallel to thefirst and second axes in the transverse direction and a mounting elementextends from the face of the insertion tool body and is configured to bereceived in the insertion tool receiving hole.
 7. The kit of claim 1,further comprising a fastener positioned in each fastener hole, each ofthe fasteners including a shaft and the shafts are parallel to oneanother in the transverse direction.